The brand of kings on the move to push limits

Patek Philippe is often referred to as the "king of brands and brand of kings", famous for
complicated timepieces which combine traditional craftmanship of highest skills and a timeless, easy to identify appearance.
This is certainly part of the brand´s philosophy; as Philippe and Thierry Stern put it, "a Patek Philippe timepiece is born from the movement, which is in
the center of the development and design process".
While the traditional values and focus on the watchmaking aspects is much appreciated among enthusiasts and collectors, a different facet of
Patek Philippe is not always recognized: innovation. Nonetheless, the history of the brand is rich of examples and a considerable number of patents granted are proof of this dedication.

Many improvements are still valid today; not only the Gyromax free-sprung balance (introduced in 1950), but pieces like the Patek Philippe "Telequartz" do remind us the brand always to be open for new fields and new solutions.
Therefore it may not come by surprise the brand will - again - introduce a true innovation. It is a stunning technical novelty: a newly developed silicon escape wheel for the swiss lever
escapement! In addition, and while not as new certainly not less remarkable, a ceramic ball bearing for the automatic winding rotor ("new" in terms of the basic
technology, which was introduced by another swiss manufacturer recently).

silicon wheel

silicon escape wheel

To start with the silicon escape wheel, the first incarnation of this new technology will be the caliber 315 with a changed fourth and escape wheel bridge, which allows a perfect view of the escape wheel. The first watch available
will be a limited series of 100 pieces (which probably will have a slightly different, even more stunning, bridge as the normal production pieces, shown in the pictures!). At the same time this edition will introduce to the new "Patek Philippe Advanced Research" concept; as Patek Philippe proudly
emphasizes, an "opportunity for a limited number of connoisseurs and collectors of technologically unusual timepieces to aquire a watch endowed with
a key milestone in horology".
It is worth noting this first limited series actually is the first step for a broader introduction of this new technique, to follow at some later point.
Therefore, the new limited edition is by no means a "high tech show piece"; actually it marks the beginning of a regular, serial production part!

Personally I find this idea very intriguing and, simply put, this seemingly simple wheel to be long overdue. For several reasons it is a very promising development and
much more admireable is the fact that Patek Philippe invested so much efforts in real technical improvements which, on the other hand, once installed will remain almost invisible, hidden deeply inside and thus not as prominent or easy to present
to the "public". It is a facet of what makes Patek Philippe so special: while other brands, in order to find a balance between costly development and effectfull PR-work, may wish to introduce the next exotic case material, Patek Philippe prefers to
add real technical and horological value. And, maybe even more important, true value and benefit for the customer.

comparison: silicon wheel (right), conventional steel wheel (left)

To combat the oldest problem in watchmaking
Within a swiss lever escapement, a technology in use for almost 100% of all wrist watch movements, the steel escape wheel together with the pallet (and ruby pallet jewels) is among the most sensitive
points, particularly in terms of (proper) lubrication. In fact most of the recent improvements at this point were based either on improved lubricants
or lubrication methods.
But even the best lubricants ar insufficient whenever the key problems is to keep them in place.
Capilarity helps the oil to creep into the jewel holes and do it´s work where it is needed.
Yet the escapement parts, escape wheel teeth and pallet jewels, are interacting in a completely different way and
lubricants in this place always have a tendency to "run away". One may improve the lubricant in order to prevent from this effect; but Patek Philippe
went ahead and a major step forward:
Given lubrication is problematic, a logical consequence is to abandon any lubrication at all.
While this is easily said, the traditional implementation of the swiss lever escapement utilizing a steel wheel and ruby pallets does not allow for such a solution.
Beyond this point, any research does have to include the search for new materials, which are able to work together without any lubrication but with similar
properties in terms of friction and long term reliability.
The new silicon escape wheel seems to be an ideal match: silicon is light, hard,
antimagnetic and resists any corrosion. Thanks to relatively new technologies it is possible to apply a surface finish of an excellent, smooth
quality.
In fact the unlubricated combination of a silicon wheel and ruby pallet does shows the same behaviour in terms of friction as the
classic combination of a steel wheel and ruby pallet in perfectly clean and freshly lubricated condition. But the benefits of the new technique reach far wider:
the main progress of the silicon wheel is the long-term stability. And it prooved to work, as long time testing showed no change in friction!
This should be one of the real and very rare progresses in an exemplary key
function of horology.

Some details
A brief description of the technology behind the silicon wheel may help to understand. When speaking of industrial applications of silicon, immediately the field of electronics comes to mind, where silicon is one of the key materials of the last decades.
One of the side effects of the tremendous research is it´s application for micro mechanics, mainly by developing completely new manufacturing processes. For electronic (mainly semi conductor) applications the silicon layer usually is very thin and does not exceed
a few thousands of a millimeter. If it comes to watch parts like the escape wheel, at least a tenth of a millimeter is necessary in order to provide sufficient stability.
The main manufacturing method is and was photolithography and etching: a photo resistant coating is applied to the surface of the silicon
slice (this slice is cut of a monochristalline silicon ingot), a glass mask protects the areas which shall remain and is exposed to UV-light. After developing (much like a photo
negative, to give an example), the remaining photo will protect this part of the silicon from etching.
There are basically two different etching methods, wet etching in a chemical wet solution and the relatively new "plasma" or dry etching,
where the etching process is achieved by gas discharge. The wet etching process isn't possible for thicker silicon layers, as it
would inevitably lead to considerable "undercut" of the vertical planes, i.e. these wouldn't remain rectangular. Plasma etching allows
perfectly rectangular vertical planes even with layers thicker than a tenth of a millimeter and thus well within the world of watch
mechanics.

silicon wafer

21st century production
A remarkable advantage of this manufacturing process is the fact the entire wheel being crafted in only one production step.
Of course the technics involved are utterly complicated and most expensive, but the advantages are impressive: a traditionally produced escape wheel needs a lot of
different steps in manufacturing, each step likely introducing a problem for keeping tight and precise tolerances (each time a part
needs fixing or indexing, precision is influenced - truly precise parts production traditionally tries to avoid repositioning, which often isn't possible).
Manufacturing an escape wheel, one of the parts where precision and high surface quality is essential, in one step in my oppinion really is a dream solution.
And knowing the traditional production of a escape wheel requires 50 production step, there are 49 possible errors ruled out in order to achieve a perfect result.

Traditional wheels are riveted to the pinion and even in this regard the new silicon wheel leads to a new approach.
Due to new materials and manufacturing methods, a new shape and method was developed:
different from the classic four spoke design of the steel wheel, the new silicon wheel has an ineresting three double spoke layout.
Three sections are forming the center hole where it is fitted on the pinion. Instead of riveting, the silicon wheel is press
fitted. This, combined with the already incredibly exact wheel itself (tolerance is told to be 1 micron!), will improve precision in sense
of running true and flat which again is very important for perfect interaction with the pallet. One of the very interesting aspects of
the silicon escape wheel is the fact that it's fully interchangeable to the traditional steel wheel. Escapement geometry remains untouched and all other
components in contact with the escape wheel (pallet, pinion) remain the same, tried parts.

ceramic ball bearing

The ceramic ball bearing marks the other important new developement. The well known steel ball bearings, introduced to horological
mechanics about fifty years ago, always turned out to be somewhat problematic for lubrication: these are very sensitive for over application of the lubricant,
even the right amount of lubricant does not provide from problems due to deterioration. The main problem beeing the steel balls starting to slide instead of
rolling and, as a result, contact corrosion or excessive wear can take place. Omitting any lubrication, which seems to work fine in the beginning, the
problems are almost the same.

The ceramic ball bearings offer a sound solution for all above; the combination fo balls made of zirconium oxide with a stainless steel inner and
outer cage does overcome all problems mentioned. These ball bearings are not depending on any lubricants at all and contact corrosion is no longer an issue.
A very convincing solution.

It should be noted, that these developements were made in cooperation with either specialized suppliers (in case of the ceramic ball
bearing) and in case of the silicon wheel the "IMT" (the Institut de Microtechnique de l'Universite de Neuchatel), the "CSEM" (Centre
Suisse Electronique et Microtechnique) and the "COMLAB" (common laboratory of both, IMT and CSEM).

Kudos to Patek Philippe and their partners in research and developement, a great and promising start for the upcoming Baselworld news!